Problem set ENERCON

1. A magnetic pole of strength 50 u.p. exerts a force of 200 dynes upon a second pole placed 5.0 cm in air away from the first pole. What is the strength of the second pole?

2. A bar magnet 8 cm long has a pole strength of 250 up. Determine the magnetic field strength at a point which is 5 cm distance from each pole.

3. Two concentric circular loops of wire of radii 9.42 and 6.28 cm respectively are connected in series. What field strength is produced at the center of the coil when there is a current of 30 a in the same direction.

4. What force would act on a pole of strength 60 up placed inside an air core toroid of 30 cm average radius, having 1000 turns and in which there is a current of 0.25 A?

5. The flux density emanating from a pole of a generator is 20000 gauss. A conductor one meter long cuts the flux at an angle of 60 degrees at a velocity of 40 m per sec. what is the voltage developed?

6. A coil has an inductance of 20 mH and carries a current of 1.2 A. how much energy is stored in the coil?

7. A solenoid with an air as core of length 20 cm and cross sectional area of 4 cm^2 contains 200 turns. It carries a current of 0.5 A. what is the magnetic induction at the center?

8. An iron ring has a mean circumference of 1 m and cross sectional area of 8 cm^2. It is wound with 600 turns of coil carrying a current of 2 A. if the flux produced is 1.5 mWb, the relative permeability of the iron is nearest to.

9. An iron ring of mean length 50 cm has an air gap of 1mm and a winding of 200 turns. If the permeability of the iron is 300 when a current of 1 A flows through the coil, find the flux density.

10. A flexible wire 1 m long is formed into a square, the plane of which is perpendicular to a uniform field of 1 mWb / m^2. Find the work done if the wire under the electromagnet forces set up when a current of 10 A is passed through it, assumes a circular shape.